NWS Forecast Models

Introduction

This module focuses on computer models that are run by the National Centers for Environmental Prediction (NCEP) and are used for forecasting the day-to-day weather in the United States. NCEP has three basic models: the North American Model (NAM), the Rapid Refresh (RAP), and the Global Forecast System (GFS). Each model is a self-contained set of computer programs which include means of analyzing data and computing the evolution of the atmosphere's winds, temperature, pressure, and moisture based on the analyses.

These individual models are all quite different from each other in one essential aspect or another, either in their formulation or their implementation. Some of these differences are particularly relevant to forecasting, while others won't make much difference to you this year. I'll be emphasizing the importances of each difference.

In this module, you will also learn the format of the model output, so you can find out what the models are predicting. Identifying different types of errors in the models will be left for the following module.

Learning Objectives

• Be able to identify each of the models by name
• Be able to read model output

Table of Contents

1. Part I
   1. Vocabulary
   2. The North American Model
   3. The Rapid Refresh Model
   4. The Global Forecast System
   5. Summary
2. Part II
   1. Model Output
   2. Handy-Dandy FOUS Decoder
   3. Handy-Dandy MOS Decoder
   4. FOUS and MOS Decoders Quiz
   5. Decoding EXT Reports
   6. Summary of Part II

Begin Part I | Begin Part II